Garmin Fishfinder 340C Owner's Manual

Also see for Fishfinder 340C: Quick reference Owner's manual Install guide Declaration of conformity Owner's manual

Fishfinder 340C Owner’s ManualgettIng stArted > understAndIng the fIshfInder And sonArUnderstanding the Fishfinder and SonarThe Fishfinder 340C is a fully automatic, color sonar unit thatallows you to go out on the water and find fish without havingto configure a lot of settings. However, you can customize eachsetting as you prefer.If you have used a Fishfinder before, you might already know howto interpret the sonar information on the screen, so you can skipthis section. If you have not used a Fishfinder before, you mightwant to learn a bit about sonar: what it is, how it works, and whatyou might see on the Fishfinder 340C screen. This manual providesa general understanding of those things that you need to knowabout sonar that can help you interpret the screen and find the fish.Understanding SonarDuring installation, you connect your Fishfinder 340C to atransducer. The transducer uses sound to determine informationabout what is in the water beneath your boat. Then the transducersends the information to your Fishfinder to be shown on the screenfor you to view and interpret.The transducer sends sound waves down into the water in a coneshape, similar to a flashlight beam (covering a smaller circular areaat the top and angling out to a larger circular area at the bottom).These sound waves reflect off of any object that they hit, and thenthe waves travel back up to the transducer. These objects couldbe fish, branches, the bottom, or any other object that has densitythat is different from the water. The transducer receives the soundwave information, and then sends the information to the Fishfinder.The Fishfinder shows the information on the screen for you to seeand interpret. The type of transducer and settings that you choosedetermine how the information appears on the screen.Using Dual FrequencyDual frequency works best for deep water (for example, off-shore)applications. The 200 kHz frequency allows you access to greatdetail about what is underneath your boat. The 50 kHz frequencyprovides less detailed information, but penetrates to greater depthswith the same power. You can choose either or both frequencies toget the information that you want. If you choose dual frequency,the transducer alternates between the 50 kHz and 200 kHz signals.This capability allows you to see the best picture available at anydepth.